Abstract: The present invention generally relates to a novel liquid disinfectant composition particularly useful in the industrial sector and the agro-food industry. This composition is in concentrated or diluted form and comprises: an aliphatic-chain fatty acid; a glycolic acid, optionally as a mixture with acetic acid; a pH-regulating system, such that the composition, in its diluted form, has a pH lower than 3.8 and preferably lower than 2.0; an ethoxylated fatty alcohol of formula R—(O—C2H4)n—OH in which R represents a linear or branched alkyl group having 6 to 12 carbon atoms and n represents an integer between 4 and 8, or a mixture of ethoxylated fatty alcohols; a copolymer of formula in which x represents an integer between 2 and 15, y represents an integer between 15 and 35, and z represents an integer between 2 and 15, or a mixture of such copolymers; one or more surfactants; and water.